1. Field of the Invention
The present invention relates to a process for producing high purity isoflavones. More particularly, the present invention relates to a process for producing high purity isoflavones by a process combining primary and secondary chromatographic steps.
2. Related Art
Isoflavones are a class of plant flavonoid compounds which have estrogenic activity. Research has revealed many possible health benefits that may be achieved from the consumption of isoflavones. High cholesterol is believed to contribute to the development of coronary heart disease and isoflavones have been demonstrated to lower cholesterol in animal studies. Isoflavones may also play a role in preventing certain types of cancer. Bone loss in women during and after menopause may also be prevented or ameliorated by isoflavones. Because of these and other potential health effects, the commercial demand for isoflavones is expected to rise rapidly.
There are a few processes already reported for isoflavone purification. U.S. Pat. No. 5,679,806 describes a process for purifying isoflavones from soy molasses by complicated chromatography and crystallization steps. U.S. Pat. No. 5,919,921 describes a process for purifying isoflavones from soy molasses by precipitation and drying. U.S. Pat. No. 5,670,632 describes a process based on chromatography using strong cation exchange resins. U.S. Pat. No. 6,320,028 describes a process for making an isoflavone product from soybeans based on extraction and precipitation. All of these reported processes are too cumbersome for the production of isoflavones on an industrial scale. Also, these processes are unable to make a high purity product. In fact, the typical purity level associated with these methods is only in the 4% to 50% range. For example, while the process disclosed in U.S. Pat. No. 6,033,714 produces an excellent isoflavone product from soy molasses, the product is typically from about 30% to about 50% isoflavones on a dry solids basis. Therefore, there is a great need for improved processes that can provide very high purity isoflavone products.